Effectiveness of avocado leaf extract (Persea americana Mill.) as antihypertensive

Abstract

Background Avocado leaves (Persea americana Mill.) have been traditionally used as antihypertensive. Various studies have tested the benefits of the Persea americana Mill. in treating hypertension but still using extracts not yet using nanoparticles. Therefore, this study aims to study the effectiveness of avocado leaf extract, including the nanoparticles, on salt-induced hypertensive Wistar rats in inhibiting the ACE enzyme, which causes decreasing systolic blood pressure (SBP) and diastolic blood pressure (DBP) as well as increasing urine volume. Methods This study used an experimental in vivo study design involving 24 white male Wistar rats (Rattus norvegicus), aged 2–3 months, weighing 130–250 g, and of a healthy condition with active movement. The samples were randomly divided into six treatment groups and post-test only research design with control group design. Results The result of the study showed that the extract contained a quercetin of 1129.597 ppm and 10 mineral compounds, including potassium, with the highest content. The analysis of antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl method showed that the antioxidant activity at IC50 was 44.734 ppm. The P. americana leaf extract nanoparticles had the most significant result in reducing blood pressure in Wistar rats induced by 16% NaCl for 14 days SBP to normal was by 68.75 mmHg (175.00±21.57 mmHg to 106.25±9.21 mmHg) and 55.25 mmHg (128.42±25.75 mmHg to 73.17±15.75 mmHg), respectively. Also, avocado leaf extract caused the decrease of SBP from 164.92±7.16 mmHg to 116.83±6.36 mmHg and DBP from 118.42±16.24 mmHg to 82.83±6.47 mmHg. The P. americana leaf extract nanoparticles resulted in the most urine volume at 13.5 ml, with the highest DAI value of 2.25. The ACE inhibitor test using the ELISA method showed that the P. americana leaf extract and the nanoparticle extract inhibition against the ACE enzyme were 60.0±12.1 % and 59.5±3%, respectively. The mean serum nitrate as a result of P. americana leaf extract (K4) and nanoparticles of P. americana leaf extract (K5) were 44.0±9.0 μmol/L and 41.1±11.5 μmol/L, respectively. The mean of serum nitrite was led by P. americana leaf extract (K4), and nanoparticles of P. americana leaf extract (K5) were 83.7±24.0 μmol/L and 81.0±23.2 μmol/L, sequentially. Conclusions The study showed that the leaf extract and nanoparticle extract of Persea americana Mill. was effective as an antihypertensive.